swiftlang/swift

[SR-540] eliminate the .cpp.gyb files from the source tree

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#43,157 opened on Jan 14, 2016

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bugcompilergood first issue

Description
Previous ID SR-540
Radar None
Original Reporter @lattner
Type Bug
Votes 0
Component/s Compiler
Labels Bug, StarterBug
Assignee None
Priority Medium

md5: ff02b1c09cc812ba86f097ddd5c3cf2d

Issue Description:

Gyb is a necessary artifact used in the standard library and test suite due to Swift not having a preprocessor. C++ on the other hand DOES have a preprocessor, so we should definitely not use gyb for .cpp files, we should use ".def" files consistently. Unfortunately we are using it in a couple of cases:

lib/Basic/UnicodeExtendedGraphemeClusters.cpp.gyb
stdlib/public/stubs/UnicodeExtendedGraphemeClusters.cpp.gyb
unittests/Basic/UnicodeGraphemeBreakTest.cpp.gyb

These should switch to using the C preprocessor.

Contributor guide

Tech stack
swiftcpp
Domain
build systemtooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++ preprocessorgyb toolSwift project build system
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75
Research direction
The issue identifies three specific files: lib/Basic/UnicodeExtendedGraphemeClusters.cpp.gyb, stdlib/public/stubs/UnicodeExtendedGraphemeClusters.cpp.gyb, and unittests/Basic/UnicodeGraphemeBreakTest.cpp.gyb. These currently use the gyb preprocessor and should be rewritten to use C preprocessor macros, likely by converting the gyb templates to .def files. The contributor should examine the gyb files to understand the current logic and then implement the equivalent using C preprocessor directives. The issue has no assignee or recent comments, so the approach should be validated by the maintainers.